The devices known for preserving a coin generally comprise a case of protection with a glass frame, in which the coin is laid out such as described in the document U.S. Pat. No. 3,100,567. Some known devices, such as the one described in the document U.S. Pat. No. 4,915,214 adapt to various diameters of coins by means of a ring whose internal and external diameters are adapted respectively to the coin and to the internal frame of the case.
The majority of the known devices only allow the protection of the coin, and not its everyday use. Thus, the structure of such devices is generally rigid and comprises closing systems that work by screwing, interlocking, or fitting. However, these devices are not easy to implement and cannot always be reopened in a simple and reliable way. Other systems have a simple structure, but are not able to ensure a sufficient protection of a coin, when the latter is meant for everyday use.